https://reddit.com/link/1syaloi/video/aethk3ae2zxg1/player
This June my pond will be 1 year old. It went through the craziest string algae bloom during a brief, unseasonably warm-up at the end of winter which continued into spring. The fast growing bloom continued for a good month before I began to get a handle on it. Today all of the string algae is gone, and has been replaced by a much less troublesome algae which is just a fuzz on the rocks. I don't mind that at all and will leave it to do what it does. I've been adding water plants to reduce the nutrients that would otherwise feed the algae. I picked up some watercress at the local market and have been delighted to see it do so well, whether placed on the waterfall, in pockets of rocks in deeper areas, or in shallow areas with lots of water movement. I recommend them for their low cost, wide availability, and fast growth. Their tiny white flowers are a bonus. I also introduced some water hyacinth and water lettuce to further reduce the nutrients in the water - I'm also hoping they grow enough by summer to provide shade over the water.
Question - can I expect a crazy spring algae bloom every year? Or will it be less once the pond has stabilized into a mature ecosystem? The only fish in the pond are a dozen small gambusia (mosquito fish), which we put in to add life and interest to the pond. I doubt they're adding a lot to fuel the algae.
The first year with this pond has been a lot more work than I expected. But it adds so much joy to our lives - I can't imagine our backyard without it.